Water Use and Management Chapter 17

Water Resources The hydrologic cycle constantly redistributes water Total: 370 billion billion gallons 500,000 km3 evaporates from oceans; 90% return Solar energy drives the cycle Water supplies are unevenly distributed Global atmospheric circulation Proximity to water sources topography

Major Water Components Oceans hold 97% of all water Regulates our planet’s atmosphere Glaciers, Ice, Snow = most surface fresh water Quickly disappearing Groundwater stores large resources Rivers, lakes, wetlands = cycle quickly Small, constantly need to be replenished Wetlands = vital Atmosphere = among the smallest of compartments

Water Availability and Use Renewable water is made up of surface runoff and infiltration While readily accessible water supplies are large, water scarcity still occurs when there is a great demand for water or poor water quality Droughts can be caused by the introduction of domestic animals, and is exacerbated by land use Water use divided into 3 parts: agricultural, domestic, and industrial, with agricultural having the greatest consumption Irrigation can be insufficient, with much water being lost through evaporation and run off (drip irrigation is a much better solution)

Water Use Cont. and Freshwater Shortages Wealthy countries use far more water than developing countries, which usually lack access to clean water Water shortages are usually caused by natural deficits, over consumption by agriculture or industry, and inadequate funds for purifying and delivering good water Ground water is being depleted by diversion projects, dams and canal systems, which have damaging effects on the environment Sedimentation and climate change affect reservoirs greatly Eventual lack of resources may lead to fights over water supplies

Conserving Getting by with less water Farmers are starting to follow the “land bank” plan, they agree to a 10-25% reduction in their water usage. Due to the depleted amount of water availability this plan benefits farmers in a way that their access to water is not shut off completely. Increasing the water supply Farmers used to pay “rain makers” in an effort to save their crops “rain makers”- person who attempts to make rain fall through rituals or scientific techniques (via seeding clouds- dry ice or KI particles) What we can do now! Shorter showers, stopping leaks, switch to drought resistant lawns.

Did you know… The largest US water use is toilet flushing US today is now conserving 144 million liters of water per day as opposed to 20 years ago Growing recognition that water is a precious and finite resource has changed policies and encouraged conservation across the US